Tiny used Blink Dagger right after Nightmare

Not sure the problem is with the bot or the item, so I thought I just post it in the bots section.

Bane cast Nightmare on Tiny, then right after the duration finishes, Tiny used Blink Dagger. Isn't the damage caused by Nightmare considered "damage from enemy hero"? If that is true, Tiny should not be able to use Blink Dagger right after Nightmare finishes and needs to wait for 3 seconds to do so.

I'm not sure if Dota 1 allowed this? Can someone clarify?

Match ID #284512

Occurred somewhere between 24:00 minutes to 25:00 minutes into the game